JPS60121652A - Sample holder for mass spectrometry - Google Patents

Abstract

PURPOSE:To reduce the pollution with a mass spectrometer due to matrix evaporation by providing a reservoir that can retain matrix such as glycerol around an area from which secondary ions are taken out by irradiating particle beam. CONSTITUTION:Space 11 is comprised with a target outside box 8 and two plates 9 and 10 and a target 12 and a glycerol retaining section 13 made of a reservoir that is formed between the target and the plates 9 and 10 using surface tension are housed in the space. Then, the irradiation area 14 between the plates 9 and 10 is coated with a sample. While the required amount of glycerol is being supplied from the circumference, the irradiation area 14 is irradiated with a primary ion 2. an emitted secondary ion 5 passes through a slit 6 and reaches a collector through an analysis section. As a result, the evaporation of unrequired glycerol can be suppressed and the pollution of the inner part of a mass spectrometer is reduced and the waste of the sample can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sample holder for a secondary ion mass spectrometer that targets organic substances.

[Background of the Invention] Determining the molecular weight and molecular structure of various substances related to living organisms is a major challenge. In order to meet this demand, a method has been developed to perform mass spectrometry on secondary ions obtained by high-speed particle bombardment. In this method, the sample is coated on a metal plate together with a large amount of glycerol or other 71~ lyx (Fig. 1), and then the sample is directly introduced under reduced pressure (10~10~10~) using a probe.
' Torr ) into the ion irradiation section. 5 for this
The matrix is sputtered by irradiating high speed ions or neutral particles with an energy of ~10 KeV, and the sample is also sputtered at the same time. At this time, some of the sputtered organic matter becomes positive or negative ions and flies out. These are called secondary ions,
This includes molecular ions in the sample. Secondary ion mass spectrometry (secondary ion mass spectrometry) collects these and performs mass analysis.
Molecular Secondary↓on Mas
s Spectrometry;
rsins).

In this method, the sample was coated with a fluid matrix such as glycerol on a nearly flat metal plate and introduced into the irradiation section. Although the vapor pressure of fluid matrices such as glycerol is low, they volatilize at a considerable rate in a vacuum. For this reason, when long-term measurements are performed, the fluid matrix adheres to the inside of the mass spectrometer, causing various troubles such as a decrease in mass resolution and sensitivity.

On the other hand, when the amount of the fluid matrix is extremely reduced, there are problems such as the inability to perform measurements in a short time and the reproducibility of spectra.

Furthermore, to explain specifically, FIG. 1 and FIG.
The conventional holding method holds the matrix 3 on the entire surface of the 2 rrtn x 5 M11100 sample holder, so the
~The area in which Rix 3 is in contact with the gas phase is large. -The secondary ions 2 are irradiated to a part of this 71-rix 3, and secondary ions 5 are emitted from there, but as shown in Figs. 1 and 2, some of these secondary ions 5 are 1-, passes through the analysis section, and reaches the collector. In this method, the surface of the matrix in contact with the gas phase is large, and a large amount of glycerol evaporates, causing contamination. Therefore, it is effective to reduce the size of the sample holder 1 (approximately 2 m + + φ), but it may not be possible to apply a sufficient amount of sample, or the three layers of matrix containing the sample may flow out to the side of the holder 1, and the gas phase The problem is that the contact area becomes large. In addition, in a normal magnetic field type mass spectrometer, only 0.0% of the sputtered secondary ions pass through the slit or analysis section and effectively reach the collector in the irradiated area.
It came out of an area of about 5mm x 5++a+. Therefore, only a small portion of the sputtered ions can be effectively used. Therefore, a holder is desired that has a structure that can minimize the area irradiated with ions and supply matrix as needed.

[Purpose of the invention]

An object of the present invention is to provide a sample holder for mass spectrometry that reduces contamination inside the mass spectrometer due to evaporation of the fluid matrix.

[Summary of the invention]

The feature of the present invention is to make the region from which secondary ions are extracted by particle beam irradiation as small as possible without impairing sensitivity, and to provide a reservoir around the region that can hold a matrix such as glycerol to reduce evaporation of the liquid matrix. There is a particular thing.

[Embodiments of the invention]

An embodiment of the present invention will be described based on FIGS. 3 to 5. One of the features of this embodiment shown in FIG. 3 is that the parts other than the ion-irradiated parts, such as the holding part for a matrix such as glycerol, are sealed to suppress glycerol vapor. As shown in FIG. 4 and FIG. 5, which is an enlarged view thereof, a space 11 is formed by the target outer box 8 and two plates 9 and 10 that are part of the target outer box 8.

A target 12 is provided in this space 11 in close contact with the outer box 8. The glycerol holding part 13 is the target 12
It is formed between the two plates 9 and 10 using surface tension. The closer you get to the ion irradiation section 14, the narrower the distance between the two plates 9, 10 becomes, and the glycerol is sent into the irradiation region 14 as necessary due to surface tension. As a result, unnecessary evaporation of glycerol can be suppressed. Conventionally, since the sample and glycerol are mixed and applied onto the target, there has been a problem that the sample concentration decreases and the S/N ratio deteriorates when measuring a very small amount of sample. However, one advantage of the present invention is that by first holding glycerol and then applying the sample to the irradiation area 14, a region with a high sample concentration can be created in the irradiation area 14, and the necessary amount of glycerol can be supplied from the surrounding area. In addition, the sample can be used effectively without wasting it.

FIG. 6 shows another embodiment of the invention, in which two plates 15.
16 is bent toward the inner space, and the surface tension of glycerol can be further utilized.

As described above, in the present invention, evaporation of organic matrices such as glycerol can be suppressed to a minimum, contamination can be prevented, and the sample density in the irradiation area can be increased to enable long-term measurement.

[Brief explanation of the drawings] Figure 1 shows an example of applying a sample on a flat surface using a conventional target, Figure 2 shows an example of a conventional target with a smaller area, and Figure 3 is a diagram showing an example of a target according to the present invention in which the portion holding glycerol is hidden inside, FIGS. 4 and 5 are cross-sectional views of the target, and FIG. 6 is a diagram showing a modified example of the present invention. be. 1... Sample holder, 2... -order beam, 3...
Sample surface, 4... Ion irradiation section, 5... Secondary ion beam, 6... Slit, 7... Secondary ion beam that can be introduced into the analysis section, 8... Target outer box of the present invention ,
9.10 Temporary, 11 Space, 12 Target, 13 Glycerol holding part, 14 Irradiation area, 15.16 Plate. 30 buds 40 buds for kaotsui

Claims (1)

[Claims] 1. A mass spectrometer having a part or reservoir capable of holding a matrix containing a sample or secondary ions obtained by irradiation with a high-speed particle beam, and a means for supplying a matrix agent little by little to the irradiation part. Corporate sample holder.